My suggestion would be to initially work on v. short sentences that she composes. Eg. start by asking what you did that day, and take a short part of her reply e.g. 'You said 'We went for a walk' - that would be an excellent thing to write. Then repeat, putting up a finger for each word. You model this, they copy. Then repeat again using the fingers (Brilliant! That's five words). Before starting to write ask them where they are going to start (and which way they will go), putting a dot on the place if necessary. Have a spare piece of paper above to use as a practice page, where they can have a go at writing words by sounding them out/seeing if they do know them or you can model slowly sounding out and write them, so they can be copied - depending on word/ability/flow. So all writing in the journal is correctly spelt. After first word written say 'Read what you've written, think what you need to write next'. Get them doing the work. Post-it notes are also good to use as a finger/s space - and depending on size of writing/how spacey you want the spaces (wide when you are teaching about them). As they become more automatic and realise how a space is used (and appropriate to size of the writing) cut the post-it into half/thinner strips. Keep them re-reading and thinking about the next word. When get to the end add full stop/exclamation or question mark as appropriate. Re-read according to punctuation. Use one post-it which gets moved along between each word - they move it i.e. they are in control of the space (praise them when they remember to move it, remind them only at the last minute, occasionally let them make a mistake and see if they spot it on the re-read - We went fora.
If the sentence is long/big writing and spaces, and they need to go on the next line ask them where they think they need to write next, if unsure ask them what happens in a book. Get them thinking about what they need to do.
Next day, re-read y.day's entry, and then compose a new one.
Progression would be to make the sentence longer - We went for a walk to the shops/Today we went for a very long walk to the big shopping centre, or adding another sentence to expand on the 'story', dropping the post it note ('make a space with your eyes') and the reminder of where to start/direction. Composing/remembering the sentence, writing (with spaces) and re-reading will become under their control. If they are writing in pen and make a mistake in their journal a white sticker can cover it and they correct over the top.
Instead of fingers, counters can be used and placed on table above as visual reminder; get the sentence composed, use fingers, five words, give them five counters, they repeat the sentence placing down a counter down as they say each word with big space between each word/counter.
V. V. wordy/laborious/non-grammatical explanation but should sort out the spaces/direction - and is quicker to do than to write about! Keep it pacey and it shouldn't take long to write a short sentence and as the sentences become longer/more sentences, they are more competent and practiced as they are doing the job by themselves.
(To really reinforce the spaces/direction, rewrite the sentence on a strip of paper. Cut it up between each word, and child puts 'puzzle' back together with space between each word. Ask them to lay it out on a piece of A4 paper, landscape, then portrait, then fold to A5, they lay it out again so they can see the 'return sweeps' work and how the full stop has to go next to to a word. nb make sure they always start top left hand of the page as if they are writing.)